Acid-base concerted mechanism in the dehydration of 1,4-butanediol over bixbyite rare earth oxide catalysts

作者：Sato Fumiya; Sato Satoshi^*; Yamada Yasuhiro; Nakamura Masashi; Shiga Akinobu

来源：Catalysis Today, 2014, 226: 124-133.

DOI：10.1016/j.cattod.2013.08.005

• Density functional study
• Paired interaction orbital
• Rare earth oxide
• Dehydration
• 1,4-Butanediol
• Acid-base concerted mechanism

Catalytic activity of rare earth oxides (REOs) in the vapor-phase dehydration of 1,4-butanediol to produce 3-buten-1-ol varies with lattice parameters of REOs. In order to clarify the adsorption structure and the reaction mechanism, adsorption energy of 1,4-butanediol on bixbyite REO, such as SC2O3, Y2O3, Dy2O3, Ho2O3, and Er2O3, {222} surface was calculated with density functional theory (DFT), and paired interacting orbitals (PIO) calculation of the adsorption state between 1,4-butanediol and Er2O3 was executed. The DFT study elucidates that the catalytic activity is correlated with adsorption energy. The PIO study clarifies the interactions between the reactive atoms of 1,4-butanediol and Er2O3 surface: tridentate interactions between a position-2 hydrogen atom of diol and an oxygen anion on Er2O3 and between each OH group of diol and erbium cations on Er2O3, and an intramolecular repulsive interaction between the position-1 carbon atom and the oxygen atom of OH group are observed. These results suggest that the position-2 hydrogen atom is firstly abstracted by a basic oxygen anion and that the position-1 hydroxyl group is subsequently abstracted by an acidic erbium cation. Another OH group on position 4 plays an important role of anchoring the diol to the Er2O3 surface. Therefore, it is proved that the dehydration of 1,4-butanediol over REOs proceeds via acid-base concerted mechanism.

• 出版日期2014-5-1